Chilling A Concrete Slab?

[Owlfarm]

Hey everybody, I'm in the planning stages of building a new warehouse and I'm thinking of running pex pipe through the concrete slab and running chilled water in it. It would be like a radiant heated floor but backwards. Ill be running undercurrent systems in the warehouse and I'm thinking this would be another way to keep the nute solution temps down, as well as the air temp in flower rooms. Anybody have any experience doing this? Any thoughts on it?

 

[germinator]

Build a basement. Concrete slab on grade will remain cool. Slab on grade at footing level will be even cooler. Plus increases the value/sq.ft of you're building. Be cheaper to cool your solution in the res with a frozen water bottles or chiller prob.

Good luck Im jealous I would love to design this for me ground up with a thick check book.

 

[fishwhistle]

Hot air rises and cold air falls so maybe having the cooling hoses on the ceiling would be more efficient?Raining down on the plants/buckets.

 

[stonestacker]

Condensation on the slab might be a problem. My barn is built into the side of a hill like a walk out basement. stays pretty cool in their sometimes when conditions are right the floor sweats real bad.
I think a chiller would be more efficient.
Keep us posted.

 

[germinator]

Condensation on the slab might be a problem. My barn is built into the side of a hill like a walk out basement. stays pretty cool in their sometimes when conditions are right the floor sweats real bad.
I think a chiller would be more efficient.
Keep us posted.

Im a big fan of thermal mass. Maybe add insulation and a visqueen vapor barrier in his floor cross section. I'm assuming we will be exhausting all moist heated air.

 

[fishwhistle]

http://en.wikipedia.org/wiki/Radiant_cooling

 

[Owlfarm]

Thanks for the link fishwhistle, looks like I need to do some further reading, but it sounds like an interesting idea. I'm a little concerned about condensation on the slab, but it might not matter to much.
I'm thinking it would be fairly cheap too. Just run pex pipe in the slab and pump water through with a chiller or heat pump.

 

[fishwhistle]

Heres a couple links for water cooling info,
http://www.hydroinnovations.com/
http://www.chillking.com/
I think your on the right track but i just dont know if its worth the cost of demoing an existing slab and pouring a new slab with pex pipe etc etc.With a chiller you can cool your water culture with a cool coil and your room too with an air handler all off the same system,very versatile,no need for imbedded pipe.Like i said before heat rises so casting radiant heat in a floor makes sense but for cooling you want it in the hottest part of your room which is the ceiling not the floor for most efficiency,heat from the bottom,cool from the top.

 

[blazer]

Never seen a cooling set up for cooling a slab I would think condensation would be a major factor would think would be Much more efficient to use coils and cool your Rez and air!
Labor intensive to run pex in a slab very costly if not doing yourself.

 

[Desertboy]

Go on ebay and buy boiler heat exchangers 2nd hand and DIY hydro innovations style iceboxs for a 1/3 the price but double the cooling power.

Icebox's are expensive for what they are.

Large thermal masses are great they will keep temp for a long time in case of power outages and just flatten out your heating and cooling costs but needs to done correctly for what it will cost I think you would want to do a small scale test first to work out how to do it properly you only have one shot at it due to cost.

 

[E.C.U.G]

I've worked with concrete for 20 years condensation will deff be a major issue. Think of how a beer bottle sweats! Now times that by a hundred.
KMK

 

[germinator]

Interesting point........we have had concrete poured in various thicknesses in many different sized industrial buildings and with proper cure time and mix we experience no long term condensation issues. On occasion we will seal a floor as requested by the owner/tenant to keep dust down. The tenants would be going crazy if all the warehouse or office floors were damp. I don't think carpet would adhere to wet concrete due to dampness from condensation, and we direct glue no padding. We pour over very prepared and inspected pad maybe that's why.

 

[fishwhistle]

Like cottonmouth im an old concrete guy myself,30+ years contractor,ive poured radiant heat systems hundreds of times but never infloor radiant cooling.I did alot of tilt up construction and refrigerated rooms and we always did the reefer rooms with foam panels on grade,steel tied over them and then slab poured over the top to trap the cold inside the room.All cooling was done with chillers and air handlers mounted from ceilings or high on walls,seems like if you cooled the slab itself half the cooling would just transfer into the ground instead of up into your room,remember heat rises and cold does not.When you cool something you are not really cooling it at all but rather removing heat from it if you can wrap your head around that concept,so you want to cool the air from the hottest place in the room which is the top(heat rises)to be most efficient.Heres a couple pics of reefer rooms,notice where the air handlers are at in the rooms?Beleive me these guys can afford to put them anywhere they want too.

https://encrypted-tbn3.invalid.com/images?q=tbn:ANd9GcSfbIDu9aVOcm1VO0XglJzD202V82nAfQs-RstF2F1RDx5SvyBQxQ

 

[Owlfarm]

Hmmm those are some good points. That's true that walk in coolers don't use radiant cooled floors. I Installed one of those this last fall.
A lot of the time they are prefab kits though, where a cooled slab wouldn't be feasible.
I'm starting from the ground up though and can design things specifically for growing.
I do think the floor would sweat like crazy though and maybe that would cause problems. My undercurrent systems sweat a lot because I run the mute temp pretty low like around 60-65 degrees and like to keep my rooms pretty hot.
I also like to run fans from the floor pulling air up to the ceiling to exchange air throughout the room. I was thinking this might help with the point fish whistle made about heat rising.
No use trying to reinvent the wheel if nobody else has tried this out for growing.
You guys have caused me to put the brakes on this for now.

 

[blazer]

Interesting point........we have had concrete poured in various thicknesses in many different sized industrial buildings and with proper cure time and mix we experience no long term condensation issues



The condensation would happen when you would attemp to cool the slab.

 

[germinator]

Love tilt up BIG monster blds.....I'm sayin cool the res liquid......the floor will stay cool. I also have not heard of cooling a floor this way if ya want floor / water probs then try infloor cooling its bound to have nuances.
But a stealth basement grow room secret doors...would be the bomb, wind n solar powered Use a cistern to hoard rain water. .ahhhh I can dream

 

[germinator]

Gotcha ..........

 

[Owlfarm]

So I've been thinking more about the chilled slab, and I'm thinking that a lot of people are already growing in basements, warehouses, garages, and greenhouses that have concrete slabs. Slabs are usually already pretty cold and a grow room is pretty warm, so if condensation was a big issue you would think this would already be happening and I haven't seen any grows with problems in this regard. So is chilling that slab really going to make that big of a difference condensation wise?

 

[blazer]

Don't see it being a efficient way of cooling don't see it be an economical at all or think it would work properly To remove heat in that configuration.
Would think Once that slab getS chilled it will condensate when the moisture in the air settles on it.
Just never seen nothing with that type of configuration for cooling maybe keeping a ice ring frozen but not to cool

 

[ShroomKing]

Chilling that slab will be almost moot. How much colder than ambient ground temperature can you sustain the slab at? And exactly half of your efficiency will be traveling downward into the ground.
But...... if you bury coiled pex below the slab and pumped geothermally cooled water up into a radiator with air pushed through it into your grow area,or even through your light hoods, might give you a temp drop with more efficient use.